1. Field of the Invention
The present invention relates to a CD (compact disc) playing apparatus and, more particularly, to an apparatus which can play a writable CD-R (CD recordable) finalized disc.
2. Description of the Related Background Art
Hitherto, a CD (compact disc) is known as a recording medium which records audio information or the like. As shown in FIG. 1(a), a lead-in area LIA in which index information of recording information has been recorded, a program area PA in which music information or the like has actually been recorded, and a lead-out area LOA indicative of the end of the program area PA are formed on the CD in order from the inner rim of the disc. The lead-in area LIA, program area PA, and lead-out area LOA are totally called an information area. A signal to be recorded is an EFM (Eight to Fourteen Modulation) modulated digital signal and includes not only main codes (main information) such as music information but also sub codes such as a time code (time information). Index information called a TOC (Table of Contents) is recorded in the lead-in area LIA. A total recording information segment number (for example, the total number of music programs) in the program area of the disc, a total recording time (for instance, the total playing time), and the like are recorded as sub codes in the lead-in area LIA. The main codes are recorded in the program area PA. A track number (TNO) indicative of the recording information segment number (for example, the music program number), a recording time (P-TIME: for instance, the playing time of the relevant music program) from the start of the relevant track, a total recording time (A-TIME: for instance, the total playing time) which is measured from the track number=1, and the like are recorded in the Q channel of the sub codes. A lead-out code indicative of the lead-out area is recorded in the lead-out area LOA.
Although the CD having such a recording format is a read only recording medium, a CD-R which can write information while using a format similar to that of the CD has been developed in recent years. The recording format standard of the CD-R is unified to the standard which is generally called "orange book" and is based on the CD format standard (generally called a red book). The CD-R disc is classified into the following three types as shown in FIG. 1(b)-1(d) in accordance with the recording state. Namely,
FIG. 1(b) illustrates a blank disc in an unrecording state in which no information is recorded yet. PA1 FIG. 1(c) illustrates a partially recorded disc (hereinafter, referred to as a PRD) on which information has partially been recorded. PA1 FIG. 1(d) illustrates a disc which has finally been formated in order to set substantially the same format as that of the CD after completion of the recording. PA1 a) When the first point data POINT="A0H" is found out, the TOC information is read out from the relevant position. Or, PA1 b) When the second point data POINT="A1H" the third point data POINT="A2H" is located, a pickup is jumped back by one track (reverse direction jump) and is returned to the inner rim side of the recording position of the first point data POINT="A0H". See FIG. 6. Subsequently, the track is searched in the forward direction and when the first point data POINT="A0H" is found out, the TOC information is read from the position at this time point.
As shown in FIG. 1(b), even in the CD-R disc, the lead-in area LIA, program are PA, and lead-out area LOA are finally formated in a manner similar to those of the CD.
Guide grooves are formed on the recording tracks of the CD-R. The guide groove is wobbled by a signal having a frequency which is obtained by frequency modulating a carrier by data (ATIP: Absolute Time In Pregroove) indicative of the absolute time information. In an information recording and reproducing apparatus for the CD-R, information is recorded and reproduced for the blank disc or partially recorded PRD by performing a tracking and spindle control by using the guide groove. As shown in FIG. 1(b), on the PRD, a PMA (Program Memory Area) as a temporary TOC area to store the recording career of the recording information is provided on the further inner rim area of an area I which is prepared for the lead-in are LIA. The following three kinds of information are recorded in the PMA. The first information relates to skip command information and skip cancel information and is information which can skip the recording information every recording information segment (track) or can skip a part (which can be designated by the time) in the recording information segment (track) when the disc is played. The first information will be described in detail hereinlater. The second information relates to a start address, an end address, and the like of the recording information recorded in the program area and they are recorded by a format similar to that of the TOC information which is recorded in the lead-in area of the CD. The third information relates to disc identification information (option) and numeral information of six digits to identify the disc can be recorded as necessary. The reason why such information is recorded as temporary TOC into the PMA is because in the PRD, there is a possibility such that information is written into the remaining program area PA, the TOC information cannot be recorded into the lead-in area LIA until the recording completion (finalization) is finally instructed.
The PRD is set into a state in which no information is written into an area I for the lead-in area LIA and an area O for the lead-out are LOA. Each area, therefore, is held in a mirror surface state. In the information recording apparatus of the CD-R, when the finalization is instructed, in order to finally obtain the same format as that of the CD, predetermined information and the TOC information recorded in the PMA are recorded as sub codes into the area I for the lead-in area LIA and a predetermined lead-out code indicative of the lead-out area LOA is recorded into the area O for the lead-out area LOA. In the conventional CD playing apparatus, consequently, the information can be reproduced from the finalized CD-R.
In case of reading the TOC information in the conventional CD playing apparatus, point data POINT="AXH" (X=0, 1, 2: H denotes the hexadecimal notation) in the sub code Q data recorded in the lead-in area LIA is searched in the direction (direction from the outer rim side of the CD to the inner rim side) opposite to the direction of the recording order of the data.
When the TOC information of the CD-R which has been finalized is read by a similar sequence by the conventional CD playing apparatus, in case of a disc which has been recorded in a mode 5 in which the skip information is recorded among the point data POINT="A1H", point data POINT="A2H", and point data POINT="A0H", even if the point data POINT="A1H" or point data POINT="A2H" is found out and the light spot is jumped back by one track, the light spot can be returned to only a position on the outer rim side of the recording position of the point data POINT="A0H". To find out the point data POINT="A0H", accordingly, it is necessary to skip one set of TOC information. There is, consequently, a problem such that it takes a long time to read the TOC information.